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Crystallofolia

Scientists have been trying to explain the unique phenomenon of “ice ribbons” for hundreds of years. But oddly, there was no consensus on what to call them. 19th century German botanists came up with “Eisblatt” (iceleaf); translated into latin it becomes “Crystallofolia”, which rolls off the tongue much more nicely. No surprise, the term was coined by linguist Dr. Bob Harms. In fact, we have Dr. Harms and Dr. James Carter (ISU professor emeritus, Geology/Geography dept.) to thank for finally demystifying the phenomenon with their careful research.

A few hours later the magic has melted, giving us a better look at the plant stem that produced it. Note the woody stem itself has not split, but a portion of the epidermis, or outer skin, has been ripped open by the expansion of the freezing sap. This is most likely to occur in early winter, when night time temperatures quickly drop below freezing after rainfall and milder weather. Only a few plant species have the right anatomy to produce crystallofolia – in Ky it’s usually found only on White Crownbeard, a tall perennial of old fields and edges, and Dittany, cunila origanoides. (And here’s your chance to be a citizen scientist – if you can positively ID the occurrence of crystallofolia (not frost) on any other species of wild plant, please send an image to Dr. Carter at jrcarter@ilstu.edu)

Carter and Harms research provides some neat insights into the process. If conditions are good, the same plant stem can produce formations night after night by pulling water up from the soil. This is done through capillary action – the same process that explains how you mop up a spilled drink with a paper towel. Though this fluid movement looks like the process of transpiration, by which living plants move water up and out, it’s apparently just using the same pathways. In his efforts to understand the process, Dr. Carter has produced similar ice formations with iron pipes!

Rouse

It’s not the same as White Snakeroot. White Crownbeard (Verbesina virginica) is closely related to Yellow Wingstem (Verbesina alternifolia). Wingstem is common in our forest but Crownbeard is not, (though it’s common in the Midwest). Crownbeard is apparently the only Verbesina that produces crystallofolia.